Agreed, and if water wicks up into the tube it becomes a mess.In the picture above, it looks like blowing into the dish/catcher is the only way for water to get in.
2 things come to mind. Try to provide a longer or steeper slope between where it comes out of the tube and the catch basin/feeder section. This will make it harder to get fluid the whole way up into the tube where it becomes a pain to clean up.
Create a shield between the tube and feeder section. If rain blowing in is the problem placing a piece of plastic wrap between the tube and the chicken wire should reduce it a good bit. Simply use a 2 ft piece regular kitchen plastic wrap to create a wind /rain break. Creative use of duct or packaging wrap tape will hold it in place (tuck corners through the chicken fence and tape it back to itself). Cheap and easy to replace as needed. If it works then you can figure on a more sturdy permanent replacement.